The present invention relates generally to the treatment presbyopia.
As the eye ages, the lens of the eye become less capable of moving to provide variable optical power, a condition referred to a presbyopia. In young subjects, the lens of the eye can accommodate viewing at various distances, so that the user can be both near and far object with clear focus. However as the eye ages, the lens of the eye becomes less capable of accommodating both near and far vision and subjects with good far vision may require glasses to read close objects.
Prior methods and apparatus of treating presbyopia provide less than ideal treatment in at least some respects. Prior treatments of presbyopia include bifocal spectacles, progressive addition lenses, and multifocal contact lenses, as well as reading glasses and accommodating intraocular lenses. At least some subjects are spectacle intolerant, and spectacles can be difficult to wear in at least some situations. Multi focal lenses can degrade vision at both near and far vision at least partially in at least some instances. Intraocular lenses require surgery and can be more invasive that would be ideal in at least some instances.
Although multifocal contact lenses have been proposed, such lenses produce less than ideal results in at least some instances. Multifocal contact lenses may have two or more optical zones of different optical power. In at least some instances, one of these zones of different optical power can transmit light to the eye that is out of focus on the retina and degrades vision of the subject. Although contact lenses that translate on the cornea have been proposed in order to provide variable focus, such lenses can be somewhat difficult for subjects to use and provide less than ideal results in at least some instances. Examples of multifocal contact lenses are described in Patent Nos.: U.S. Pat. Nos. 7,517,084; 7,322,695; 7,503,652; 6,092,899; and 7,810,925, for example.
Although accommodating contact lenses have been previously proposed, the prior accommodating contact lenses can be less than ideal in at least some instances. For example, the optical properties of the prior accommodating contact lenses can be less than ideal. For example, the shape of the central shape changing region of the prior accommodating contact lenses can be somewhat distorted when the eye accommodates, and the accommodating optical zone can be somewhat smaller than would be ideal. Also, the optical zones the prior lenses can be shaped somewhat irregularly and may provide less than ideal changes in optical power. Also, the materials of the prior accommodating contact lenses can be less than ideally suited for combination with known contact lens materials, and the extent to which prior accommodating contact lenses can be worn on the eye is less than ideal in at least some instances. Accommodating contact lenses are described in WO 91/10154; U.S. Pat. Nos. 7,699,462; 7,694,464; and 7,452,075, for example.
In addition to the deficiencies noted above, work in relation to embodiments also suggests that the prior accommodating contact lenses are less than ideally suited for manufacturing, and that at least some of the prior accommodating contact lenses may be difficult to produce in large volumes in at least some instances.
Ideally, an improved accommodating contact lens will provide accommodation to the user, be easy to use, provide quality near vision, intermediate and far vision, be compatible with known safe contact lens materials, and be readily manufactured. At least some of these objectives are met with the embodiments as disclosed herein.